We all know too well the effects cigarettes can have on the human body and science has told us it can lead to many health issues, including cancer.

This does not mean that everyone who smokes a cigarette — or does so for a weekend, year or longer — will get cancer, nor is there a specific time set on when people will cross the threshold of serious harm due to smoking.

What about using this rationale concerning drinking water? No, we’re not saying the effects on the body are anywhere close to being the same, nor do we want to create undue fear that cigarette smoke inhalation and unhealthy water are in any way linked.

Instead, look at the mindset, or the difference in the way we look at the two.

Science tells us untreated water can lead to a host of health issues. So communities, rightfully, chlorinate to protect people from these health risks.

However, there are byproducts of the chlorination process that also have the potential to cause health problems, albeit over longer exposure. One of those is trihalomethanes (THMs).

What do scientists, the experts in the field say about THMs?

The World Health Organization draws attention to THMs in an article on Water Sanitation and Health (find it here) that says the effects of THMs on humans are largely misunderstood but “associations were found between ingestion of chlorinated drinking water and the incidences of colon cancer for those aged 60 years or more (Cragle et al., 1985) and bladder cancer among non-smokers … In Ontario, King & Marrett (1996) found an increased bladder cancer risk with increasing duration of exposure and THM levels.” It went on to say the longer the exposure the increased the risk.

According to an article in the World Academy of Science, Engineering and Technology (find it here) there is a “connection between lengthy exposure to chlorinated drinking water and bladder cancer. This risk increases after exposure for many years. This risk is not very big, but because many people are exposed to chlorinated drinking water for many years, this risk is significant because cases of bladder cancer can be attributed to disinfection byproducts.”

In 2013, John Werring, the senior science and policy adviser with the David Suzuki Foundation, speaking about high levels of THMs in Newfoundland and Labrador, said the “longer that action (reducing THMs) is delayed, the more possibility more and more people will get sick.”

Tahir Husain, a Memorial University professor with a PhD, has been studying this issue in this province for more than 20 years.

“Once the level is two-three times (higher than Health Canada standards), and people have been drinking that same water for a long period of time — like 10, 15 or 20 years, then one should get concerned about that,” he said.

More studies offer the same conclusions: we know it’s bad for you, we know it has the potential to be very serious, but we don’t know how long it takes to cause harm.

So, what can communities do? The provincial government’s take on how municipalities should deal with high levels of THMs is blunt: “If you are above the Health Canada standards, by god you should be informing your residents that is the case,” said Graham Leto, provincial Municipal Affairs minister Graham Letto, himself a former mayor. “For liability and accountability purposes, you should be doing that and municipalities have to take some responsibility in that.”

Exactly what does taking “responsibility” mean?

It means being upfront. It means looking out for residents well above political interests.

It’s being honest and leaving scientists to scientific analysis.

It means not recommending people consume water that Health Canada says carries the potential for harm.